When Dinosaurs Ruled the Earth is a 1970 monster horror film starring Victoria Vetri, set in the time of cavemen. The film was made by Britain's Hammer Films. Like several of Hammer's previous films, such as One Million Years B.C. (1966), the film anachronistically portrays dinosaurs and humans alongside each other. Directed and scripted by Val Guest, it was based on a treatment by J. G. Ballard (author of Empire of the Sun), and nominated for an Oscar for its visual effects. The special effects are considered a benchmark in stop-motion animation believability, and the film is referenced in the movie Jurassic Park. A tribe on a cliff are about to sacrifice three blonde women. Three priests, wearing dinosaur hides, are about to kill them for their Sun God, but one of them, Sanna, escapes and jumps off the cliff. She is rescued by Tara and some men on a raft. Tara takes Sanna to his seaside tribe, who also worship the Sun God. After building a Hut for herself, She joins them at a feast and celebration of a successful hunt. A Plesiosaur attacks the seaside tribe until it is lured to a store of Oil and immolated.